We have built a cw, diode-laser-pumped, Nd;YAG slab laser that emits 72 W of multimode power when pumped with 235 W, or 40 W of TEM00 power when pumped with 212 W of diode laser power. The slope efficiencies are 36% for multimode operation and 22% for TEM00 mode operation. The laser uses the zig-zag slab geometry to reduce the thermal effects associated with high power operation, resulting in less than one wave of distortion at the full pump power. Reasonable efficiency for the side- pumped slab design was obtained by confining the pump power within a gold-coated box which surrounds the slab. TEM00 mode operation was obtained in a simple three-mirror folded cavity. The Nd:YAG slab acted as an aperture in the cavity and the astigmatism due to off axis incidence on a curved mirror corrected for a minor 1 meter cylindrical thermal lens. A significant advantage of our design over previous slab lasers is a new Teflon AF protective coating on the slab total internal reflection surfaces which greatly simplifies the mounting and cooling of the slab laser medium.© (1995) COPYRIGHT SPIE--The International Society for Optical Engineering. Downloading of the abstract is permitted for personal use only.